D.N. Basov Department of Physics University of California, San Diego

Low Frequency Dynamics of Correlated Electron Systems

NSLS-II workshop March 15, 2004

Doped Mott-Hubbard Insulators spectral weight transfer spin/charge inhomogeneities

High-Tc superconductors inhomogeneous condensate pairing “glue” energetics2D electron gas and FET structures magnetic organic FET

IR @NSLS-II

Experimental issues New opportunities

Low Frequency Dynamics of Correlated Electron Systems

D.N. Basov Department of Physics University of California, San Diego

Magnetism inter-metallic ferromagnets ferromagnetic semiconductors magnetic resonances left-handed media

Sub-THz Far-IR mid-IR - visible UV

10 100 1000 10000 cm-1

1 10 100 1000 meV

“Infrared” spectroscopy @ UCSD

Low Frequency Dynamics of Correlated Electron Systems

pseudogaps

superconducting energy gap carrier lifetimes in correlated systems

collective modes in correlated systemsphonons

electronic transitions

1 10 100 1000 10000 cm-1

100 1000GHz 100 1000meVIR s e trosco UCSD

IR spectroscopy @ UCSD

2D Electron gas: EF

(magnetic) polarons

Cyclotron resonances

pseudogaps

superconducting energy gap carrier lifetimes in correlated systems

collective modes in correlated systemsphonons

electronic transitions

1 10 100 1000 10000 cm-1

100 1000GHz 100 1000meVIR s e trosco UCSD

IR spectroscopy @ UCSD

2D Electron gas: EF

(magnetic) polarons

Cyclotron resonances

1. Broad spectral coverage

2. Optical constants and sum rules

3. Anisotropy

4. Large probing thickness

5. Micro-crystals

: σσσσ1111(ω)(ω)(ω)(ω) + + + + iσσσσ2222(ω)(ω)(ω)(ω)

Low Frequency Dynamics of Correlated Electron Systems

6. Extreme experimental conditions:mK temperatureshigh magnetic fieldhigh electric fieldultra-high pressure

0 2 4 6eV

0

1000

2000

3000

D:\talks\2002\all-meeting-may\mott-hubba

0 2 4 6 eV

0

1000

2000

3000

0 1 2 3 4eV

0

400

800

1200

10 K

σ(ω), [Ωcm]-1 σ(ω), [Ωcm]-1 σ(ω), [Ωcm]-11. Doped Mott-Hubbard Insulators

6 eV 6 eV 4 eV

La2-xSrxCuO4La1-xSrxVO3La1-xSrxMnO3F.Inaba et al.PRB 52, 2221 (95)

Y.OkimotoPRB 51, 9581 (95)

S.Uchida et al.PRB 43, 7942 (91)

Experimental issues: High-ωωωω data is needed for KK analysis

R(ωωωω) data at ωωωω < 36 eV

x=0

x=0.34

x=0x=0

x=0.4x=0.3

Beam-line based ellipsometry

IR @NSLS-II

2. Doped Mott-Hubbard Insulators: T dependence

V2O3M.Rozenberg et al.PRL 75, 105 (95)

170 K

300 K

70 K

0.0 0.4 0.8 1.2 1.6eV

0

1000

2000

3000

σ(ω), [Ωcm]-1

Experimental issues: T, H dependence of σ(ω)σ(ω)σ(ω)σ(ω)over anomalously broad ωωωω range

Accurate data over broad ωωωω intervals Beam-line based ellipsometry

( )em

nd =∫∞

ωσω 10

IR @NSLS-II

3. Doped M-H Insulators: charge inhomogeneities

CuO2

CuO2

CuO2

⊥EIIE

0 100 200 300

0

500

1000

0 100 2000

500

1000

a axis b axis

Temperature (K)

σdc (Ω

-1cm-1)

13 K a axis b axis

σ1 (Ω

-1cm-1)

Frequency (cm-1)

II⊥

II⊥

La1.96Sr0.04CuO4

M.Dumm, S.Komiya, Y.Ando, D.N.Basov, PRL 91, 077004 (03).

IR @NSLS-II

Experimental issues: Micro-crystals

High intensity, Beam-line based IR microscopy Photo-inducedeffects

CuO2

CuO2

CuO2

0.5 1.0 1.5 ω/ω0

0.04

0.08

0.12

0.16

Im(1

/ε)

6 K

20 30 40 50 cm-1

0.5

1.0

R(ω

)

6 K

S.Dordevic, S.Komiya, Y.Ando, D.N.Basov, PRL 91, 167401 (03)

“Josephson plasmon microscopy”

4. Doped MH Insulators: inhomogeneous superconductivity

0

0.02

0.04

0.06

0.08

Im(1

/ε)

R(ω

)

15 K

GHz

cm-1

0.5 1.0 1.5 ω/ω0

0.04

0.08

0.12

0.16

Im(1

/ε)

6 K

20 30 40 50 cm-1

0.5

1.0

R(ω

)

6 K

E.J.Singley et al. PRB (in press)ALS-BESSY collaboration

“Josephson plasmon microscopy”

Experimental issues: Sub-THz ωωωω region

IR @NSLS-II

“coherent” radiation

S.Dordevic, S.Komiya, Y.Ando, D.N.Basov, PRL 91, 167401 (03)

4. Doped MH Insulators: inhomogeneous superconductivity

0 400 800 1200 1600 cm-1

0

1

2

W(ω

)

neutron

W(ω)

5. High-TC superconductivity: pairing interaction

Experimental issues: Second derivative of 1/τ(ω)/τ(ω)/τ(ω)/τ(ω)

0 40 80 120 160cm-1

0

0.4

0.8

1.2

As

An

R.R.Joyce and P.L. Richards PRL 24, 1007 (67)

Beamline-based ellipsometry

Magnetic? P.D.Johnson RPL 87, 177007 (01), Hwang et al. Nature (04)consistent with ARPES, tunneling,

Phonons? /A.Lanzara et al. Nature 412, 510 (2001)/… but no isotope effect /N.Wang et al. PRL 89, 87003 (03)

J.Carbotte, E.Schachinger, D.N.BasovNature 401, 354 (1999)

Phonon DOS(neutrons)

( ) ( )

=ωσ

ωωπ

ω 1Re21

2

2

ddW

Pb

IR @NSLS-II Magneto-optics

H.J.A.Molengraaf et al. Science 295, 2239 (2002)

gordon/fig/form-for-fig4-all

kinetic energy sum rule

∫σ1

W

0dω = −Kr

6. High-TC superconductivity: energetics at T<<TC

Experimental issues:Small effects involving broad ωωωω range

La2-xSrxCuO4

YBa2Cu3O6.6

0 500 1000 cm-1

0.0

0.5

1.0

[Nn(ω

) - N

s(ω )]

__

____

____

__

ρs

0.0

0.5

1.0

56 kTc

Nn(ω

) - N

s(ω )

____

____

____

ρ

s

0 40 80 120 meV

22 kTc

Synchrotron-basedellipsometry

IR @NSLS-II

D.N. Basov, S.I. Woods, A.S.Katz, E.J. Singley,R.C. Dynes, M. Xu, D.G. Hinks, C.C. Homes, M.Strongin, Science 283, 49 (1999)

10 100 T, (K)N

eff

0

10

20

30

M(T

), (e

mu/

cm3 )10 100 T, (K)

2000300040005000

ωp

cm-1

EuB6L.Degiorgi et al.PRL 79, 5134 (97)

Ga1-xMnxAsE.J.Singley, PRL89, (2002)

Y.Okimoto et al.PRL 75, 109 (95)

0 100 200 300 T, (K)0.000.020.040.06

Nef

f

0.00.20.40.60.81.0

M(T

)/M0La1-xSrxMnO3

La1-xSrxMnO3

Experimental issues:Bandwidth? “Undressing” effect?

Beamline-based ellipsometry

7. Magnetism: itinerant intermetallic ferromagnets

IR @NSLS-II

8. Magnetism: optical control of magnetic state

S.Koshihara et al. PRL78, 4617 (1997)

In1-xMnxAs

A.Oiwa, Y.Mitsumori, T.Slupinski, H.Munekata,PRL 88, 137202 (2002)

IR @NSLS-II

Pump-probe experiments

AF

9. Magnetism: AF resonance in the frequency domain

Experimental issues:Sub-THz regionSmall transmission

Intensity! IR @NSLS-II

LaMnO3

L. Mihály, D. Talbayev, L. F. Kiss, J. Zhou, T. Fehér, and A. Jánossy Phys. Rev. B 69, 024414 (2004)

10. Magnetic resonances and “Left-handed” media

D.R.Smith et al.PRL 84, 4184 2000

(+,+)(-,+)

(-,-) (+,-)

ε,µε,µε,µε,µ space

V.G.VeselagoSov. Phys. Uspekhi 10, 509 (1968)

Irrelevant?Split-ring resonator design J.B. Pendry et al. PRL 76, 4773 (1996)

10. Magnetic resonances and “Left-handed” media

(+,+)(-,+)

(-,-) (+,-)

ε,µε,µε,µε,µ space

T.J. Yen, et al. Science 303, 1494 (04)

Experimental challenges:1. Tunable?• Real materials?

IR @NSLS-II

Photo-dopingFET-dopingIR ellipsometry

11. FET structures:

H. Ohno, D. Chiba, F. Matsukura, T. Omiya, E. Abe, T. Dietl, Y. Ohno& K. Ohtani, Nature 408, 944 (2000).

pentacene Poly(3-hexylthiophene)

V.Y. Butko*, X. Chi, D. V. Lang,A.P. Ramirez APL 83, 4773 (03)

G. Wang, D. Moses, A.J. Heeger,J. Applied Phys. 95, 316 (04)

FM semiconductors

Organic molecular crystals

Polymers

pentacene Poly(3-hexylthiophene)

V.Y. Butko*, X. Chi, D. V. Lang,A.P. Ramirez APL 83, 4773 (03)

G. Wang, D. Moses, A.J. Heeger,J. Applied Phys. 95, 316 (04)

H. Ohno, D. Chiba, F. Matsukura, T. Omiya, E. Abe, T. Dietl, Y. Ohno& K. Ohtani, Nature 408, 944 (2000).

11. FET structures

gateoxide

CRYSTAL

IR INTERFEROMETER

detector

S D

Spectroscopy @ NSLS-2 and Correlated Electron Systems

IR• Instruments for broad range spectroscopy: (80 GHz - 30 eV )

• “Coherent” radiation for sub-THz region

• Spectroscopic ellipsometry

• Pump-probe experiments

• Micro-sample capabilities

• High magnetic field